Communication using VLANs (Virtual Local Area Networks) has been performed. In a system that shares a network, the VLANs can divide and use the network. For example, in a system in which a plurality of communication apparatuses (hubs) are connected, by performing VLAN settings in connection ports of the communication apparatuses (the hubs), one network in physical arrangement can be logically operated as a plurality of networks. Such a technology is disclosed in Patent Literatures 1 to 3.